Effect of Central Pedestrian Refuges on Calming of Traffic in Their Vicinity

Abstract

Central pedestrian refuges are one of the traffic calming measures used in small towns and villages located on through routes. Their main function is to protect vulnerable road users from safety hazards and reduce the 85th percentile speed v85 before the island. In order to determine the efficiency of the central refuges in obtaining reduction of v85 speed to the desired level before the islands the authors measured the speeds both before and after the islands of different width in specific locations along the stretch i.e. in the entry, central and in the exit zones. The central refuges were typically 2 m wide, imposing a 1 m deflection of vehicles. Other deflections, namely by 2.5 m and 3 m were imposed by two of the analysed islands. In one case the vehicle path was not deflected, namely at the refuge/chicane combination located on the departure lane. The research covered in total ten different cases of crossings in villages on regional roads. Most of the analysed pedestrian islands were accompanied with hatched areas before and after the island with a conventional 1:5 taper. All the islands are located in a residential areas, yet with different types of adjacent developments. In all the analysed cases the maximum permitted speed during daytime was 50 km/h. Speed measurements were carried out with special traffic detection devices equipped with automatic traffic speed and volume recording function. The analyses considered free-flow average and v85 speeds. In a few cases buildings were located close to the roadway edge right after the central refuge. In the other cases the road was surrounded by a rural area or a forest. In two cases the island was followed by a horizontal curve affecting the sight line. The desired speed reduction or reduction down to the statutory speed for residential areas before the island was not obtained in all the analysed cases. In a few cases average speed under free-flow conditions of ca. 50 km/h and v85 speed of 55 km/h were obtained for the islands located in the village centres with houses located close to the road edge. Without residential buildings located close to the road edge before the island and with a restricted view on the further course of the road reduction of both speeds was obtained after the island. Smaller speeds were noted also on the road sections where greater horizontal deflections were imposed. The greatest speed reduction along the island was noted on the sections with reduced visibility or with residential buildings in close proximity. The degree of deflection was found to have a smaller effect.